Fifth planet (hypothetical)
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In the history of astronomy, a handful of Solar System bodies other than Jupiter have been counted as the fifth planet from the Sun. Various hypotheses have also postulated the former existence of a f
Ceres, the only dwarf planet in the asteroid belt, was once categorized as a planet.
Ceres (dwarf planet)
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Ceres is a dwarf planet in the main asteroid belt between the orbits of Mars and Jupiter. It was the first object identified in the asteroid belt, discovered on 1 January 1801 by Giuseppe Piazzi at Pa
Fifth planet (hypothetical)
…During the early 19th century, as asteroids were discovered, they were considered to be planets. Jupiter became the sixth planet with the discovery of Ceres in 1801. Soon, three more asteroids, Pallas (1802), Juno (1804), and Vesta (1807) were discovered. They were counted as separate planets, even though…
Ceres (bottom left), the Moon and Earth, shown to scale
Relative mean diameters of the four largest minor planets in the asteroid belt (dwarf planet Ceres at left)
Ceres, polar regions (November 2015): North (left); south (right). The south pole is in shadow. "Ysolo Mons" has since been renamed "Yamor Mons."